Prior art locks for locking a door to a door frame comprises a pin or bolt that is movable between a retracted position to unlock the door from the door frame and an extended position to lock the door to the door frame.
In traditional locks, the pin of the lock is actuated between the retracted and extended positions by a key for turning a mechanism for moving the pin. Modern locks may comprise an actuator such as an electric motor for moving the pin between the retracted and extended positions. Such locks may be controlled remotely by a security system. When driving the pin from the extended position to the retracted position using an actuator such as a motor, the retraction rate of the pin is governed by the speed of the motor. The motor may move the pin at a relatively slow speed. Further, the actuator and mechanism for moving the pin must have sufficient power to move the pin from the extended position to the retracted position under onerous conditions, for example when a load is applied to a door that causes a force to be applied to the pin that the lock must overcome to retract the pin to unlock the door.
A lock that comprises an electrical actuator for driving the lock pin may be configured to a fail-open mode or a fail-close mode. In a fail-open mode, when the door is closed and locked and electrical power to the lock is cut, the lock automatically retracts the pin to unlock the door. Conversely, in a fail-close mode, when a door is closed unlocked and electrical power to the lock is cut, the lock automatically extends the pin to lock the door. A lock may be configurable to set the lock as a fail-close or fail-open lock. Configuration of such a lock may not be straight forward and may require multiple mechanical and electrical adjustments to be made.
When a door swings shut from an open position to a closed position, the pin must extend once the door is closed so that the pin aligns with an opening for receiving the pin to lock the door to a door frame. If the pin extends before the lock is sufficiently aligned with a lock strike plate, the pin can jam the door in an open position. Furthermore, a lock for locking a double swing door must be capable of locking a door when the door approaches a door frame from either of two directions.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide an improved door lock or to at least provide the public with a useful choice.